Inkjet printers operate by sweeping a pen with one or more inkjet nozzles above a print medium and applying a precision quantity of liquid ink from specified nozzles as they pass over specified pixel locations on the print medium.
The print medium becomes damper and remains damp for a longer time as more ink is applied on the same area of the print medium. As a first approximation, the drying time, before which the ink is not subject to smearing by contact with an adjacent sheet is a linear function of amount of ink applied. In certain prior art inkjet printers, a fixed delay is introduced between any physical contact between successively printed sheets, which is greater than the maximum time required to dry the densest possible image to the point that it is not susceptible to smearing. However, this unnecessarily restricts throughput when the printed images on some pages do not contain any densely inked portions and/or when large unprinted areas appear on succeeding pages which can be completely bypassed by the print head.
Thus, the prior art has failed to provide a satisfactory solution for printing a high quality graphics image at a high throughput rate, which is further exacerbated if additional dots of ink are selectively applied between adjacent pixels, thereby effectively doubling the number of dots of ink, in order to increase image density and/or to provide smoother boundaries for any curved or diagonal images ("Resolution Enhancement Technology").